Replacement cylinder for hydraulic jacks



June 19, 1962 v. R. TRENT 3,039,400

REPLACEMENT CYLINDER FOR HYDRAULIC JACKS Filed Aug. 19, 1959 Fig. F /'g.2

q. W (N 24 l| 46 44 BY g g/ 19 Venn/e R. Trent INVENTOR.

United States Patent 1 3,039,400 REPLACEMENT CYLINDER FOR HYDRAULICJACKS Vonnie R. Trent, Del City, Okla. (417 W. California St, GkiahomaCity 4', Okla.) Filed Aug. 19, 1959, Sell. N0. 834,728 7 Claims. (Cl.10321;6)

This invention relates to a novel and useful replace ment cylinder forhydraulic jacks and more particularly to a replacement cylinder which isadapted to be removably secured within a jack pump body to restore theworm surfaces of the pump body cylinder to its original dimensions andcondition.

Many types of hydraulic jacks, and particularly those used for thepurpose of raising and lowering motor vehicles to assist in the repairof the latter, are constructed in such a manner as to provide relativelylong periods of trouble free operation. However, for various reasonssuch as the entrance of water or other foreign materials into the fluidpassageways of the jack, the cylinder from which the fluid is pumpedinto the ram of the jack becomes pitted or scarred and thus renderedincapable of efficiently performing its function.

Such hydraulic jacks are initially relatively expensive and it is mostdesirable to be able to restore the jack to its original eflicientcondition without necessitating the replacement of the entire hydraulicsystem of the jack.

Of course, the pump cylinder could be quite readily bored oversize andprovided with a similar oversized piston, but this would necessarilychange the ratio between the area of the pump piston and the area of theram piston which in some instances could be undesirable such as when thejack ram is required to move precise distances in response to a giventravel of the pump piston. It would also require that hydraulic jackmanufacturers maintain a supply of various dimensioned oversized pumppistons which would be economically undesirable.

Although the automotive industry has found it to be advantageous toprovide ioversized pistons for automobile engines, this would not be thecase with the manufacturers of hydraulic jacks since there are differentconditions present and a substantially smaller number of a given make ofjack being manufactured which would necessarily maintain the cost ofoversized hydraulic jack pump pistons relatively high because of thelimited number that would be produced.

It is therefore the main object of this invention to provide a meanswhereby a hydraulic jack pump may have its cylinder replaced with acylinder of identical internal dimensions.

A further object of this'invention is to provide a replaceable pumpcylinder for hydraulic jacks that may be installed in the pump body ofa'hydraulic jack with a minimum amount of alterations to the pump body.

Still another object of invention, in accordance with the precedingobjects, is toprovide a replaceable hydraulic jack pump cylinder whichmay be itself readily replaced should the need arise.

A still further object of this invention is to provide a replaceablecylinder fo a hydraulic jack pump which ice of construction andoperation as more fully hereinafter described and claimed, referencebeing bad to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a side elevation-a1 view of a portion of a conventional formof hydraulic jack pump such as that utilized in the Hein-Werner models0, 08, W and WS hydraulic floor jacks, parts of the pump body beingbroken away and shown in section and the piston and piston guideassembly being removed;

FIGURE 2 is -a side elevational view, similar to FIG- URE l, of the pumpbody but shown in a modifiedbored and counterbored condition inpreparation for the securement of the replaceable cylinder comprisingthe instant invention therein;

FIGURE 3 is a side elevational view, similar to FIG- URE 2, of the pumpbut with the replaceable cylinder shown secured therein and with thepiston and piston guide assembly shown mounted in the replaceablecylinder; and

FIGURE 4 is an enlarged perspective view of'the replaceable cylinder.

Referring now more specifically to the drawings, the numeral 10generally designates a conventional form of hydraulic pump body, as forexample that of the Hein- Werner models 0, OS, W and WS, having a blindbore12 formed therein provided with an enlarged outer counterbore 14which is internally threaded as at 16 adjacent its junction with thebore 12. A fluid passageway 18 communicates with the inner end portionof the blind bore 12 and serves as a passageway for hydraulic fluid toenter and exit from the blind bore or pump cylinder 12 under theoperation of la piston therein.

It is to be understood that the passageway 18 also communicates with afluid reservoir (not shown) and the hydraulic ram (not shown) of thejack, there being provided suitable check valves (not shown) between theblind bore 12 and the reservoir and the hydraulic ram.

The hydraulic pump shown in FIGURE 1 is typical of the conventional formof hydraulic pump used in certain conventional forms of hydraulic jacksand with attention directed more particularly to FIGURE 2 of thedrawings it will be seen that in preparation to receive a removable orreplace-able cylinder, the hydraulic pump body is bored as at 20 andprovided withfirst and second counterbores 22 and 24 respectively.

The replaceable pump cylinder comprising the present invention isgenerally designated by the reference numeral 26 and includes acylindrical body having an intermediate portion 28 terminating in adiametrically enlarged portion 30 on one end and a diametrically reducedportion 32 on the other end.

Formed in the cylindrical body and extending from the enlarged endportion 30 to -a point adjacent the reduced end portion 32 is a blindbore 34 which is provided with an outer counterbore 36 that isinternally threaded as at 3s.

The intermediate portion 28 is provided with a peripheral groove 40which is in alignment with and communicates with passageway 18. At leastone aperture 42 is formed in the intermediate portion 28 of thecylindrical body 26 which communicates the blind bore 34 with theperipheral groove 40 in order to continuously communicate the blind bore34 with the passageway 18.

The diametrically reduced end portion 32 is threaded as at 44 and thereis provided a threaded fastener 46 for the purpose of removably securingthe cylindrical body 26 within the pump body 10.

The intermediate portion 28 is also provided with an annular groove 48in which is seated an O-ring 50 for the purpose of providing a fluidseal between the intermediate portion 28 and the first counterbore 22.

The diametrically enlarged portion 30 is shorter than the secondcounterbore 24 and there is disposed between the shoulder of thediametrically enlarged end portion 30 and the adjacent shoulder of thepump body 141 an annular fluid seal 52 for the purpose of establishing afluid seal between the intermediate portion 28 and the secondcounterbore 24.

Seated in the threaded portion 38 of the enlarged bore 36 is a pistonguide 54 having a bore (not shown) formed therethrough for the purposeof guiding the pump piston 56 during its reciprocatory movement in theblind bore 34. The upper portion of the piston 56 is provided with adiametrically reduced end portion 58 to which is secured in anyconvenient manner a retaining Washer 6% between which and the pistonguide 54 is disposed a compression spring 62 for the purpose of normallyurging the piston 56 toward a position with its lower or inner end inthe upper or outer portion of the blind bore 34.

It is to be understood that the counterbores 2t and 24 are of suflicientdiameter to enable a cylindrical body 26 to be snugly received thereinwith a blind bore 34 and enlarged bore 36 formed therein equal indimensions to the original blind bore 12 and counterbore 14 so as toenable the pump body to be restored to its original operating conditionwith a piston 56 of the same diameter as the original piston. Further,it is to be noted that once the pump body 10 has been modified by theprovision of the bore 20 and counterbores Z2 and 24, that thereplaceable cylindrical body 26 may itself be readily replaced merelyupon the removal of the threaded fastener 46. In this manner, wheneverit becomes necessary, the pump cylinder and the piston and guideassemblies may be readily replaced by relatively unskilled labor.

It is to be understood that the replaceable cylinder 76 may also beincorporated in the manufacture of new jacks which would enable thereplacement of the original cylinder much faster with great ease.Incorporation of the replaceable cylinder 24 in new jacks wouldeliminate the need for boring out the pump body when the cylinder isreplaced. Further, the enlarged end portion 30 can be made shorter inlength to provide a recess for receiving a flexible boot or sectionalmetal dust shield in the upper end of the counter bore 24 to provide ameans for restricting the entrance of foreign material into the hydraulic jack system.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. In combination with a pump body of the type having a body bore formedtherethrough having first and second counterbores and with a fluidpassage in said body communicating 'With said first counter bore, afluid pump comprising a cylindrical body having an intermediate portionwith diametrically enlarged and reduced end portions on opposite ends,said cylindrical body having a longitudinal blind bore formed thereinand terminating at its inner end adjacent said reduced portion, theouter end of said blind bore including an enlarged counter bore disposedin said enlarged portion, a cylindrical piston guide, means removablysecuring and seating said piston guide in said enlarged bore adjacentthe inner end thereof, the inner surfaces of said guide formingcontinuations of the noncountered bore portion of said blind bore, apiston slidably disposed in said piston guide and extending into saidblind bore, means normally urging said piston outwardly towards aposition with the inner end thereof extending slightly into saidlast-mentioned non-counterbored portion of said blind bore, saidintermediate and enlarged portions of said cylindrical body snuglyreceived and seated in said first and second counterbores with saidreduced portion snugly received in and extending through said pump bodybore, means communicating the inner portion of said blind bore with saidfluid passage, and means securing the reduced portion of saidcylindrical body through said pump body bore.

2. The combination of claim 1 wherein said communicating means comprisesa peripheral groove formed in said intermediate portion registering withsaid fluid passage, at least one connecting aperture formed in saidcylindrical body communicating said groove with said blind bore.

3. The combination of claim 1 wherein said piston guide is threadinglyengaged in said counterbore of said cylindrical body.

4. The combination of claim 1 including a fluid seal between said pumpbody and said cylindrical body intermediate said fluid passage and theremote end of said body bore.

5. The combination of claim 1 including a fluid seal between said pumpbody and said cylindrical body intermediate said fluid passage and theremote end of said second counter bore.

6. The combination of claim 1 including a fluid seal between said pumpbody and said cylindrical body intermediate said fluid passage and theremote end of said body bore, a fluid seal between said pump body andsaid cylindrical body intermediate said fluid passage and the remote endof said second counterbore.

7. The combination of claim 1 wherein said reduced portion is externallythreaded, said securing means comprising a threaded fastener.

References (Iited in the file of this patent UNITED STATES PATENTS1,904,115 Bacon Apr. 18, 1933 1,969,920 Andrews Aug. 14, 1934 1,976,903Tear Oct. 16, 1934 2,518,787 Huhtala Aug. 15, 1950 2,732,805 Lucien Jan.31, 1956 FOREIGN PATENTS 1,164,596 France Oct. 13, 1958

